Digestive system Flashcards
Where does the digestive/ GI tract begin and end
Begins at oral cavity, continues thr pharynx, esophagus, stomach, small intestine, large intestines and ends at rectum and anus
What are the accessory digestive organs
Teeth, tongue and glands (salivary glands, liver, pancrease, gallblader)
State the functions of digestive system
Ingestion, where food and drink enter the oral cavity of digestive tract
Mechanical processing: crushing and shearing to make solid food easier to propel along digestive tract
Digestion: Chemical breakdown of food into small organic fragments for absorption by digestive epithelium
Secretion: Releases water, acids, enzymes and buffers by epithelium of digestive tract, glandular organs and gallbladder
Absorption: Movement of organic substrates, electrolytes, vitamins and water across digestive epithelium into interstital fluid of digestive tract
Excretion: Removal of waste products from body fluids
What does the lining of the digestive tract protect the surrounding tissues from
Corrosive effects of digestive acids and enzymes, physical stress and bacteria, either swallowed with food or reside in digestive tract
What is peristalsis
Waves of muscular contraction that moves a bolus along the length of the digestive tract
Circular muscle contract first behind bolus (food), then longtidunal. The wave of contration in circular muscle layer forces bolus forward
What is segmentation
Churning and breaking up digestive materials, mixes contents with intestinal secretion
What does the tongue
Manipulates materials inside mouth
Fuctions of tongue
Mechanical processing (compression, abrasion and distortion)
manipulation (asist chewing and preapre for swallowing)
sensory analysis (touch, temperatue and taste receptors)
secretion (mucin and enzyme lingual lipase)
What are the three salivary glands
Parotid salivary gland
Sublingual salivary gland
Submandibular salivary gland
What are the three phases of swallowing/ deglutition
buccal phase, pharyngeal phase and esophageal phase
What is the function of stomach
Storage oand mechanical breakdown of ingested food
Disrupt chemical bonds in food by acid and enzymes
Produce intrinstic factor for vitamin B12 absorption in small intestine
What is chyme
Ingested substances mix with secretion of glands of stomach
What are the three phases of gastric acitivity
Cephalic phase
Gastric phase
Intestinal phase
What is the function of the small intestine
Digestion and absorption of nutrients
What are the three segments of the small intestine
Duodenum, jejunum, lleum
What is the function of the duodenum
“mixing bowl” recieving chyme from stomach and digestive secretion from pancreas and liver
what is the function of jejunum
Bulk chemical digestion and nutrition absorption
What is the function of lleum
Ends at ileocecal valve, a sphincter that controls flow of material from ileum into the large intestine
What is the plicae circulares in the small intestine
Transverse folds in the intestinal lining
What are Intestinal villi
Fingerlike projections carpeted with microvilli that increase surface area
State the function of the intestinal glands
replenish intestinal epithelium
Secrete watery intestinal juice
Produce intestinal hormones
What is the function of the pancreas (IMPT)
Secretes hormones insulin, glucagon and digestive enzymes, discharges secretion into duodenum
What is the function of the liver
Metabolic regulation
Hematological regulation
Bile production
- contains bilirubin (pigment from haemoglobin)
What is the function of the gallbladder
Stores, concentrates and modify bile prior to excretion into duodenum sphincter
What does bile do
Bile emulsifies fats, breaks them down into smaller particles so taht pancreatic enzyme lipase can digest them
What are the four parts of the large intestine
Cecum (stores materials and begins compaction)
Appendix (dominated by lymphoid nodules)
Colon (has four segments, ascending, transverse, descending and sigmoid)
Rectum (movement of fecal material into recum triggers urge to defecate)
Anus (exit of the anal canal)
State the functions of the large intestine
Reabsorption of water and compaction of intestinal content into feces
Absorption of important vitamins freed by bacterial action
Storage of fecal material prior to defecation
What enzymes disolves carbohydrates and which part of the body produces them
Amylase (salivary gland and pancreas)
Maltase, sucrase and lactase (small intestine)
What enzyme dissolves proteins and which part of the body produces them
pepsin (stomach)
Trypsin, (pancrease) - protein to polypeptides
Peptidases (small intestine)
how to rmb: the ones that dont start with the p is from the p
What enzyme dissolves lipase and which part of the body produces them
Lipase (pancrease)
Bile (liver)- helps with emulsification
